{"id":1570,"date":"2022-11-15T23:02:56","date_gmt":"2022-11-15T15:02:56","guid":{"rendered":"https:\/\/qaqaq.top\/?p=1570"},"modified":"2022-11-27T12:40:58","modified_gmt":"2022-11-27T04:40:58","slug":"global%e4%b8%8esession%e7%b3%bb%e7%bb%9f%e5%8f%98%e9%87%8f%e7%9a%84%e4%bd%bf%e7%94%a8%e3%80%81%e4%bc%9a%e8%af%9d%e7%94%a8%e6%88%b7%e5%8f%98%e9%87%8f%e4%b8%8e%e5%b1%80%e9%83%a8%e5%8f%98%e9%87%8f","status":"publish","type":"post","link":"https:\/\/qaqaq.top\/?p=1570","title":{"rendered":"GLOBAL\u4e0eSESSION\u7cfb\u7edf\u53d8\u91cf\u7684\u4f7f\u7528\u3001\u4f1a\u8bdd\u7528\u6237\u53d8\u91cf\u4e0e\u5c40\u90e8\u53d8\u91cf\u7684\u4f7f\u7528\u3001\u7a0b\u5e8f\u51fa\u9519\u7684\u5904\u7406\u673a\u5236\u3001\u5206\u652f\u7ed3\u6784IF\u7684\u4f7f\u7528\u3001\u5206\u652f\u7ed3\u6784CASE\u7684\u4f7f\u7528\u3001LOOP_WHILE_REPEAT\u4e09\u79cd\u5faa\u73af\u7ed3\u6784\u3001LEAVE\u548cITERATE\u7684\u4f7f\u7528\u3001\u6e38\u6807\u7684\u4f7f\u7528"},"content":{"rendered":"\n<pre class=\"wp-block-code\"><code># \u7b2c16\u7ae0_\u53d8\u91cf\u3001\u6d41\u7a0b\u63a7\u5236\u4e0e\u6e38\u6807\r\n\r\n# 1. \u53d8\u91cf\r\n# 1.1 \u53d8\u91cf\uff1a\u7cfb\u7edf\u53d8\u91cf\uff08\u5168\u5c40\u7cfb\u7edf\u53d8\u91cf\u3001\u4f1a\u8bdd\u7cfb\u7edf\u53d8\u91cf\uff09 vs \u7528\u6237\u81ea\u5b9a\u4e49\u53d8\u91cf\r\n\r\n# 1.2 \u67e5\u770b\u7cfb\u7edf\u53d8\u91cf\r\n#\u67e5\u8be2\u5168\u5c40\u7cfb\u7edf\u53d8\u91cf\r\nSHOW GLOBAL VARIABLES; #617\r\n#\u67e5\u8be2\u4f1a\u8bdd\u7cfb\u7edf\u53d8\u91cf\r\nSHOW SESSION VARIABLES; #640\r\n\r\nSHOW VARIABLES; #\u9ed8\u8ba4\u67e5\u8be2\u7684\u662f\u4f1a\u8bdd\u7cfb\u7edf\u53d8\u91cf\r\n\r\n#\u67e5\u8be2\u90e8\u5206\u7cfb\u7edf\u53d8\u91cf\r\n\r\nSHOW GLOBAL VARIABLES LIKE 'admin_%';\r\n\r\nSHOW VARIABLES LIKE 'character_%';\r\n\r\n# 1.3 \u67e5\u770b\u6307\u5b9a\u7cfb\u7edf\u53d8\u91cf\r\n\r\nSELECT @@global.max_connections;\r\nSELECT @@global.character_set_client;\r\n\r\n#\u9519\u8bef\uff1a\r\nSELECT @@global.pseudo_thread_id;\r\n\r\n#\u9519\u8bef\uff1a\r\nSELECT @@session.max_connections;\r\n\r\nSELECT @@session.character_set_client;\r\n\r\nSELECT @@session.pseudo_thread_id;\r\n\r\nSELECT @@character_set_client; #\u5148\u67e5\u8be2\u4f1a\u8bdd\u7cfb\u7edf\u53d8\u91cf\uff0c\u518d\u67e5\u8be2\u5168\u5c40\u7cfb\u7edf\u53d8\u91cf\r\n\r\n# 1.4 \u4fee\u6539\u7cfb\u7edf\u53d8\u91cf\u7684\u503c\r\n# \u5168\u5c40\u7cfb\u7edf\u53d8\u91cf\uff1a\r\n#\u65b9\u5f0f1\uff1a\r\nSET @@global.max_connections = 161;\r\n#\u65b9\u5f0f2\uff1a\r\nSET GLOBAL max_connections = 171;\r\n\r\n#\u9488\u5bf9\u4e8e\u5f53\u524d\u7684\u6570\u636e\u5e93\u5b9e\u4f8b\u662f\u6709\u6548\u7684\uff0c\u4e00\u65e6\u91cd\u542fmysql\u670d\u52a1\uff0c\u5c31\u5931\u6548\u4e86\u3002\r\n\r\n# \u4f1a\u8bdd\u7cfb\u7edf\u53d8\u91cf\uff1a\r\n#\u65b9\u5f0f1\uff1a\r\nSET @@session.character_set_client = 'gbk';\r\n#\u65b9\u5f0f2\uff1a\r\nSET SESSION character_set_client = 'gbk';\r\n\r\n#\u9488\u5bf9\u4e8e\u5f53\u524d\u4f1a\u8bdd\u662f\u6709\u6548\u7684\uff0c\u4e00\u65e6\u7ed3\u675f\u4f1a\u8bdd\uff0c\u91cd\u65b0\u5efa\u7acb\u8d77\u65b0\u7684\u4f1a\u8bdd\uff0c\u5c31\u5931\u6548\u4e86\u3002\r\n\r\n# 1.5 \u7528\u6237\u53d8\u91cf\r\n\/*\r\n \u2460 \u7528\u6237\u53d8\u91cf\uff1a\u4f1a\u8bdd\u7528\u6237\u53d8\u91cf vs \u5c40\u90e8\u53d8\u91cf\r\n\r\n \u2461 \u4f1a\u8bdd\u7528\u6237\u53d8\u91cf\uff1a\u4f7f\u7528\"@\"\u5f00\u5934\uff0c\u4f5c\u7528\u57df\u4e3a\u5f53\u524d\u4f1a\u8bdd\u3002\r\n \u2462 \u5c40\u90e8\u53d8\u91cf\uff1a\u53ea\u80fd\u4f7f\u7528\u5728\u5b58\u50a8\u8fc7\u7a0b\u548c\u5b58\u50a8\u51fd\u6570\u4e2d\u7684\u3002\r\n\r\n *\/\r\n\r\n# 1.6 \u4f1a\u8bdd\u7528\u6237\u53d8\u91cf\r\n\/*\r\n\u2460 \u53d8\u91cf\u7684\u58f0\u660e\u548c\u8d4b\u503c\uff1a\r\n    #\u65b9\u5f0f1\uff1a\u201c=\u201d\u6216\u201c:=\u201d\r\n    SET @\u7528\u6237\u53d8\u91cf = \u503c;\r\n    SET @\u7528\u6237\u53d8\u91cf := \u503c;\r\n\r\n    #\u65b9\u5f0f2\uff1a\u201c:=\u201d \u6216 INTO\u5173\u952e\u5b57\r\n    SELECT @\u7528\u6237\u53d8\u91cf := \u8868\u8fbe\u5f0f &#91;FROM \u7b49\u5b50\u53e5];\r\n    SELECT \u8868\u8fbe\u5f0f INTO @\u7528\u6237\u53d8\u91cf &#91;FROM \u7b49\u5b50\u53e5];\r\n\r\n\u2461 \u4f7f\u7528\r\nSELECT @\u53d8\u91cf\u540d\r\n *\/\r\n#\u51c6\u5907\u5de5\u4f5c\r\nCREATE DATABASE dbtest16;\r\n\r\nUSE dbtest16;\r\n\r\nCREATE TABLE employees\r\nAS\r\n    SELECT * FROM atguigudb.employees;\r\n\r\nCREATE TABLE departments\r\nAS\r\n    SELECT * FROM atguigudb.departments;\r\n\r\nSELECT * FROM employees;\r\nSELECT * FROM departments;\r\n\r\n#\u6d4b\u8bd5\uff1a\r\n#\u65b9\u5f0f1\uff1a\r\nSET @m1 = 1;\r\nSET @m2 := 2;\r\nSET @sum := @m1 + @m2;\r\n\r\nSELECT @sum;\r\n\r\n#\u65b9\u5f0f2\uff1a\r\nSELECT @count := COUNT(*) FROM employees;\r\n\r\nSELECT @count;\r\n\r\nSELECT AVG(salary) INTO @avg_sal FROM employees;\r\n\r\nSELECT @avg_sal;\r\n\r\n# 1.7 \u5c40\u90e8\u53d8\u91cf\r\n\/*\r\n 1\u3001\u5c40\u90e8\u53d8\u91cf\u5fc5\u987b\u6ee1\u8db3\uff1a\r\n \u2460 \u4f7f\u7528DECLARE\u58f0\u660e\r\n \u2461 \u58f0\u660e\u5e76\u4f7f\u7528\u5728BEGIN ... END \u4e2d \uff08\u4f7f\u7528\u5728\u5b58\u50a8\u8fc7\u7a0b\u3001\u5b58\u50a8\u51fd\u6570\u4e2d\uff09\r\n \u2462 DECLARE\u7684\u65b9\u5f0f\u58f0\u660e\u7684\u5c40\u90e8\u53d8\u91cf\u5fc5\u987b\u58f0\u660e\u5728BEGIN\u4e2d\u7684\u9996\u884c\u7684\u4f4d\u7f6e\u3002\r\n\r\n 2\u3001\u58f0\u660e\u683c\u5f0f\uff1a\r\n DECLARE \u53d8\u91cf\u540d \u7c7b\u578b &#91;default \u503c]; # \u5982\u679c\u6ca1\u6709DEFAULT\u5b50\u53e5\uff0c\u521d\u59cb\u503c\u4e3aNULL\r\n\r\n 3\u3001\u8d4b\u503c\uff1a\r\n \u65b9\u5f0f1\uff1a\r\n SET \u53d8\u91cf\u540d=\u503c;\r\n SET \u53d8\u91cf\u540d:=\u503c;\r\n \u65b9\u5f0f2\uff1a\r\n SELECT \u5b57\u6bb5\u540d\u6216\u8868\u8fbe\u5f0f INTO \u53d8\u91cf\u540d FROM \u8868;\r\n\r\n 4\u3001\u4f7f\u7528\r\n SELECT \u5c40\u90e8\u53d8\u91cf\u540d;\r\n *\/\r\n\r\n#\u4e3e\u4f8b\uff1a\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE test_var()\r\n\r\nBEGIN\r\n   #1\u3001\u58f0\u660e\u5c40\u90e8\u53d8\u91cf\r\n    DECLARE a INT DEFAULT 0;\r\n   DECLARE b INT;\r\n   #DECLARE a,b INT DEFAULT 0;\r\n   DECLARE emp_name VARCHAR(25);\r\n\r\n   #2\u3001\u8d4b\u503c\r\n    SET a = 1;\r\n   SET b := 2;\r\n\r\n   SELECT last_name INTO emp_name FROM employees WHERE employee_id = 101;\r\n\r\n   #3\u3001\u4f7f\u7528\r\n    SELECT a,b,emp_name;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b\r\nCALL test_var();\r\n\r\n# \u4e3e\u4f8b1\uff1a\u58f0\u660e\u5c40\u90e8\u53d8\u91cf\uff0c\u5e76\u5206\u522b\u8d4b\u503c\u4e3aemployees\u8868\u4e2demployee_id\u4e3a102\u7684last_name\u548csalary\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE test_pro()\r\nBEGIN\r\n    #\u58f0\u660e\r\n    DECLARE emp_name VARCHAR(25);\r\n    DECLARE sal DOUBLE(10,2) DEFAULT 0.0;\r\n    #\u8d4b\u503c\r\n    SELECT last_name,salary INTO emp_name,sal\r\n    FROM employees\r\n        WHERE employee_id = 102;\r\n    #\u4f7f\u7528\r\n    SELECT emp_name,sal;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b\r\n\r\nCALL test_pro();\r\n\r\nSELECT last_name,salary FROM employees\r\nWHERE employee_id = 102;\r\n\r\n# \u4e3e\u4f8b2\uff1a\u58f0\u660e\u4e24\u4e2a\u53d8\u91cf\uff0c\u6c42\u548c\u5e76\u6253\u5370 \uff08\u5206\u522b\u4f7f\u7528\u4f1a\u8bdd\u7528\u6237\u53d8\u91cf\u3001\u5c40\u90e8\u53d8\u91cf\u7684\u65b9\u5f0f\u5b9e\u73b0\uff09\r\n\r\n#\u65b9\u5f0f1\uff1a\u4f7f\u7528\u4f1a\u8bdd\u7528\u6237\u53d8\u91cf\r\n\r\nSET @v1 = 10;\r\nSET @v2 := 20;\r\nSET @result := @v1 + @v2;\r\n\r\n#\u67e5\u770b\r\nSELECT @result;\r\n\r\n#\u65b9\u5f0f2\uff1a\u4f7f\u7528\u5c40\u90e8\u53d8\u91cf\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE add_value()\r\nBEGIN\r\n   #\u58f0\u660e\r\n    DECLARE vaule1,value2,sum_val INT;\r\n\r\n   #\u8d4b\u503c\r\n    SET vaule1 = 10;\r\n   SET value2 := 100;\r\n\r\n   SET sum_val = vaule1 + value2;\r\n\r\n   #\u4f7f\u7528\r\n    SELECT sum_val;\r\n\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b\r\nCALL add_value();\r\n\r\n# \u4e3e\u4f8b3\uff1a\u521b\u5efa\u5b58\u50a8\u8fc7\u7a0b\u201cdifferent_salary\u201d\u67e5\u8be2\u67d0\u5458\u5de5\u548c\u4ed6\u9886\u5bfc\u7684\u85aa\u8d44\u5dee\u8ddd\uff0c\u5e76\u7528IN\u53c2\u6570emp_id\u63a5\u6536\u5458\u5de5id\uff0c\r\n# \u7528OUT\u53c2\u6570dif_salary\u8f93\u51fa\u85aa\u8d44\u5dee\u8ddd\u7ed3\u679c\u3002\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE different_salary(IN emp_id INT,OUT dif_salary DOUBLE)\r\nBEGIN\r\n   #\u5206\u6790\uff1a\u67e5\u8be2\u51faemp_id\u5458\u5de5\u7684\u5de5\u8d44\uff1b\u67e5\u8be2\u51faemp_id\u5458\u5de5\u7684\u7ba1\u7406\u8005\u7684id\uff1b\u67e5\u8be2\u7ba1\u7406\u8005id\u7684\u5de5\u8d44\uff1b\u8ba1\u7b97\u4e24\u4e2a\u5de5\u8d44\u7684\u5dee\u503c\r\n\r\n    #\u58f0\u660e\u53d8\u91cf\r\n    DECLARE emp_sal DOUBLE DEFAULT 0.0; #\u8bb0\u5f55\u5458\u5de5\u7684\u5de5\u8d44\r\n    DECLARE mgr_sal DOUBLE DEFAULT 0.0; #\u8bb0\u5f55\u7ba1\u7406\u8005\u7684\u5de5\u8d44\r\n\r\n    DECLARE mgr_id INT DEFAULT 0; #\u8bb0\u5f55\u7ba1\u7406\u8005\u7684id\r\n\r\n    #\u8d4b\u503c\r\n    SELECT salary INTO emp_sal FROM employees WHERE employee_id = emp_id;\r\n\r\n   SELECT manager_id INTO mgr_id FROM employees WHERE employee_id = emp_id;\r\n   SELECT salary INTO mgr_sal FROM employees WHERE employee_id = mgr_id;\r\n\r\n   SET dif_salary = mgr_sal - emp_sal;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b\r\nSET @emp_id := 103;\r\nSET @dif_sal := 0;\r\nCALL different_salary(@emp_id,@dif_sal);\r\n\r\nSELECT @dif_sal;\r\n\r\nSELECT * FROM employees;\r\n\r\n# 2. \u5b9a\u4e49\u6761\u4ef6\u548c\u5904\u7406\u7a0b\u5e8f\r\n\r\n# 2.1 \u9519\u8bef\u6f14\u793a\uff1a\r\n\r\n# \u9519\u8bef\u4ee3\u7801\uff1a1364\r\n# Field 'email' doesn't have a default value\r\nINSERT INTO employees(last_name)\r\nVALUES('Tom');\r\n\r\nDESC employees;\r\n\r\n#\u9519\u8bef\u6f14\u793a\uff1a\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE UpdateDataNoCondition()\r\nBEGIN\r\n    SET @x = 1;\r\n    UPDATE employees SET email = NULL WHERE last_name = 'Abel';\r\n    SET @x = 2;\r\n    UPDATE employees SET email = 'aabbel' WHERE last_name = 'Abel';\r\n    SET @x = 3;\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b\r\n#\u9519\u8bef\u4ee3\u7801\uff1a1048\r\n#Column 'email' cannot be null\r\nCALL UpdateDataNoCondition();\r\n\r\nSELECT @x;\r\n\r\n# 2.2 \u5b9a\u4e49\u6761\u4ef6\r\n# \u683c\u5f0f\uff1aDECLARE \u9519\u8bef\u540d\u79f0 CONDITION FOR \u9519\u8bef\u7801\uff08\u6216\u9519\u8bef\u6761\u4ef6\uff09\r\n\r\n# \u4e3e\u4f8b1\uff1a\u5b9a\u4e49\u201cField_Not_Be_NULL\u201d\u9519\u8bef\u540d\u4e0eMySQL\u4e2d\u8fdd\u53cd\u975e\u7a7a\u7ea6\u675f\u7684\u9519\u8bef\u7c7b\u578b\r\n# \u662f\u201cERROR 1048 (23000)\u201d\u5bf9\u5e94\u3002\r\n#\u65b9\u5f0f1\uff1a\u4f7f\u7528MySQL_error_code\r\nDECLARE Field_Not_Be_NULL CONDITION FOR 1048;\r\n\r\n#\u65b9\u5f0f2\uff1a\u4f7f\u7528sqlstare_value\r\nDECLARE Field_Not_Be_NULL CONDITION FOR SQLSTATE '23000';\r\n\r\n# \u4e3e\u4f8b2\uff1a\u5b9a\u4e49\"ERROR 1148(42000)\"\u9519\u8bef\uff0c\u540d\u79f0\u4e3acommand_not_allowed\u3002\r\nDECLARE command_not_allowed CONDITION FOR 1148;\r\n\r\nDECLARE command_not_allowed CONDITION FOR SQLSTATE '42000';\r\n\r\n# 2.3 \u5b9a\u4e49\u5904\u7406\u7a0b\u5e8f\r\n#\u683c\u5f0f\uff1aDECLARE \u5904\u7406\u65b9\u5f0f HANDLER FOR \u9519\u8bef\u7c7b\u578b \u5904\u7406\u8bed\u53e5\r\n\r\n# \u4e3e\u4f8b\uff1a\r\n#\u65b9\u6cd51\uff1a\u6355\u83b7sqlstate_value\r\nDECLARE CONTINUE HANDLER FOR SQLSTATE '42S02' SET @info = 'NO_SUCH_TABLE';\r\n\r\n#\u65b9\u6cd52\uff1a\u6355\u83b7mysql_error_value\r\nDECLARE CONTINUE HANDLER FOR 1146 SET @info = 'NO_SUCH_TABLE';\r\n\r\n#\u65b9\u6cd53\uff1a\u5148\u5b9a\u4e49\u6761\u4ef6\uff0c\u518d\u8c03\u7528\r\nDECLARE no_such_table CONDITION FOR 1146;\r\nDECLARE CONTINUE HANDLER FOR NO_SUCH_TABLE SET @info = 'NO_SUCH_TABLE';\r\n\r\n#\u65b9\u6cd54\uff1a\u4f7f\u7528SQLWARNING\r\nDECLARE EXIT HANDLER FOR SQLWARNING SET @info = 'ERROR';\r\n\r\n#\u65b9\u6cd55\uff1a\u4f7f\u7528NOT FOUND\r\nDECLARE EXIT HANDLER FOR NOT FOUND SET @info = 'NO_SUCH_TABLE';\r\n\r\n#\u65b9\u6cd56\uff1a\u4f7f\u7528SQLEXCEPTION\r\nDECLARE EXIT HANDLER FOR SQLEXCEPTION SET @info = 'ERROR';\r\n\r\n# 2.4 \u6848\u4f8b\u7684\u5904\u7406\r\n\r\nDROP PROCEDURE UpdateDataNoCondition;\r\n\r\n#\u91cd\u65b0\u5b9a\u4e49\u5b58\u50a8\u8fc7\u7a0b\uff1a\u4f53\u73b0\u9519\u8bef\u7684\u5904\u7406\u7a0b\u5e8f\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE UpdateDataNoCondition()\r\nBEGIN\r\n    #\u58f0\u660e\u5904\u7406\u7a0b\u5e8f\r\n    #\u5904\u7406\u65b9\u5f0f1\uff1a\r\n    DECLARE CONTINUE HANDLER FOR 1048 SET @prc_value = -1;\r\n    #\u5904\u7406\u65b9\u5f0f2\uff1a\r\n#     DECLARE CONTINUE HANDLER FOR SQLSTATE '23000' SET @prc_value = -1;\r\n\r\n    SET @x = 1;\r\n    UPDATE employees SET email = NULL WHERE last_name = 'Abel';\r\n    SET @x = 2;\r\n    UPDATE employees SET email = 'aabbel' WHERE last_name = 'Abel';\r\n    SET @x = 3;\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b\uff1a\r\nCALL UpdateDataNoCondition();\r\n\r\n#\u67e5\u770b\u53d8\u91cf\uff1a\r\nSELECT @x,@prc_value;\r\n\r\n# 2.5 \u518d\u4e3e\u4e00\u4e2a\u4f8b\u5b50\uff1a\r\n#\u521b\u5efa\u4e00\u4e2a\u540d\u79f0\u4e3a\u201cInsertDataWithCondition\u201d\u7684\u5b58\u50a8\u8fc7\u7a0b\r\n\r\n#\u2460 \u51c6\u5907\u5de5\u4f5c\r\nCREATE TABLE departments\r\nAS\r\nSELECT * FROM atguigudb.`departments`;\r\n\r\nDESC departments;\r\n\r\nALTER TABLE departments\r\nADD CONSTRAINT uk_dept_name UNIQUE(department_id);\r\n\r\n#\u2461 \u5b9a\u4e49\u5b58\u50a8\u8fc7\u7a0b\uff1a\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE InsertDataWithCondition()\r\nBEGIN\r\n    SET @x = 1;\r\n    INSERT INTO departments(department_name) VALUES('\u6d4b\u8bd5');\r\n    SET @x = 2;\r\n    INSERT INTO departments(department_name) VALUES('\u6d4b\u8bd5');\r\n    SET @x = 3;\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u2462 \u8c03\u7528\r\nCALL InsertDataWithCondition();\r\n\r\nSELECT @x;  #2\r\n\r\n#\u2463 \u5220\u9664\u6b64\u5b58\u50a8\u8fc7\u7a0b\r\nDROP PROCEDURE IF EXISTS InsertDataWithCondition;\r\n\r\n#\u2464 \u91cd\u65b0\u5b9a\u4e49\u5b58\u50a8\u8fc7\u7a0b\uff08\u8003\u8651\u5230\u9519\u8bef\u7684\u5904\u7406\u7a0b\u5e8f\uff09\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE InsertDataWithCondition()\r\nBEGIN\r\n\r\n    #\u5904\u7406\u7a0b\u5e8f\r\n    #\u65b9\u5f0f1\uff1a\r\n#     DECLARE EXIT HANDLER FOR 1062 SET @pro_value = -1;\r\n    #\u65b9\u5f0f2\uff1a\r\n#     DECLARE EXIT HANDLER FOR SQLSTATE '23000' SET @pro_value = -1;\r\n    #\u65b9\u5f0f3\uff1a\r\n    #\u5b9a\u4e49\u6761\u4ef6\r\n    DECLARE duplicate_entry CONDITION FOR 1062;\r\n    DECLARE EXIT HANDLER FOR  duplicate_entry SET @pro_value = -1;\r\n\r\n    SET @x = 1;\r\n    INSERT INTO departments(department_name) VALUES('\u6d4b\u8bd5');\r\n    SET @x = 2;\r\n    INSERT INTO departments(department_name) VALUES('\u6d4b\u8bd5');\r\n    SET @x = 3;\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n# \u8c03\u7528\r\nCALL InsertDataWithCondition();\r\n\r\nSELECT @x,@pro_value;\r\n\r\n# 3. \u6d41\u7a0b\u63a7\u5236\r\n# 3.1 \u5206\u652f\u7ed3\u6784\u4e4b IF\r\n\r\n#\u4e3e\u4f8b1\uff1a\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE test_if()\r\n\r\nBEGIN\r\n#     #\u60c5\u51b51\uff1a\r\n#    #\u58f0\u660e\u5c40\u90e8\u53d8\u91cf\r\n#     DECLARE stu_name VARCHAR(15);\r\n#\r\n#    IF stu_name IS NULL\r\n#        THEN SELECT 'stu_name is null';\r\n#        END IF;\r\n\r\n#     #\u60c5\u51b52\uff1a\r\n#     DECLARE email VARCHAR(25) DEFAULT 'aaa';\r\n#\r\n#     IF email IS NULL\r\n#         THEN SELECT 'email is null';\r\n#     ELSE\r\n#         SELECT 'email is not null';\r\n#         END IF;\r\n\r\n    #\u60c5\u51b53\uff1a\u591a\u9009\u4e00\r\n    DECLARE age INT DEFAULT 20;\r\n\r\n    IF age > 40\r\n        THEN SELECT '\u4e2d\u8001\u5e74';\r\n    ELSEIF age > 18\r\n        THEN SELECT '\u9752\u58ee\u5e74';\r\n    ELSEIF age > 8\r\n        THEN SELECT '\u9752\u5c11\u5e74';\r\n    ELSE\r\n        SELECT '\u5a74\u5e7c\u513f';\r\n        END IF;\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL test_if();\r\n\r\nDROP PROCEDURE test_if;\r\n\r\n# \u4e3e\u4f8b2\uff1a\u58f0\u660e\u5b58\u50a8\u8fc7\u7a0b\u201cupdate_salary_by_eid1\u201d\uff0c\u5b9a\u4e49IN\u53c2\u6570emp_id\uff0c\r\n# \u8f93\u5165\u5458\u5de5\u7f16\u53f7\u3002\u5224\u65ad\u8be5\u5458\u5de5\u85aa\u8d44\u5982\u679c\u4f4e\u4e8e8000\u5143\u5e76\u4e14\u5165\u804c\u65f6\u95f4\u8d85\u8fc75\u5e74\uff0c\u5c31\u6da8\u85aa500\u5143\uff1b\u5426\u5219\u5c31\u4e0d\u53d8\u3002\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE update_salary_by_eid1(IN emp_id INT)\r\nBEGIN\r\n    #\u58f0\u660e\u5c40\u90e8\u53d8\u91cf\r\n    DECLARE emp_sal DOUBLE; #\u8bb0\u5f55\u5458\u5de5\u7684\u5de5\u8d44\r\n    DECLARE hire_year DOUBLE;   #\u8bb0\u5f55\u5458\u5de5\u5165\u804c\u516c\u53f8\u7684\u5e74\u5934\r\n\r\n    #\u8d4b\u503c\r\n    SELECT salary INTO emp_sal FROM employees WHERE employee_id = emp_id;\r\n\r\n    SELECT DATEDIFF(CURDATE(),hire_date) \/ 365 INTO hire_year FROM employees WHERE employee_id = emp_id;\r\n\r\n    #\u5224\u65ad\r\n    IF emp_sal &lt; 8000 AND hire_year >= 5\r\n        THEN UPDATE employees SET salary = salary + 500 WHERE employee_id = emp_id;\r\n        END IF;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b\r\nCALL update_salary_by_eid1(104);\r\n\r\nSELECT DATEDIFF(CURDATE(),hire_date) \/ 365,employee_id,salary\r\nFROM employees\r\nWHERE salary &lt; 8000 AND DATEDIFF(CURDATE(),hire_date) \/ 365 >= 5;\r\n\r\nDROP PROCEDURE update_salary_by_eid1;\r\n\r\n# \u4e3e\u4f8b3\uff1a\u58f0\u660e\u5b58\u50a8\u8fc7\u7a0b\u201cupdate_salary_by_eid2\u201d\uff0c\u5b9a\u4e49IN\u53c2\u6570emp_id\uff0c\u8f93\u5165\u5458\u5de5\u7f16\u53f7\u3002\r\n# \u5224\u65ad\u8be5\u5458\u5de5\u85aa\u8d44\u5982\u679c\u4f4e\u4e8e9000\u5143\u5e76\u4e14\u5165\u804c\u65f6\u95f4\u8d85\u8fc75\u5e74\uff0c\u5c31\u6da8\u85aa500\u5143\uff1b\u5426\u5219\u5c31\u6da8\u85aa100\u5143\u3002\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE update_salary_by_eid2(IN emp_id INT)\r\nBEGIN\r\n    #\u58f0\u660e\u5c40\u90e8\u53d8\u91cf\r\n    DECLARE emp_sal DOUBLE; #\u8bb0\u5f55\u5458\u5de5\u7684\u5de5\u8d44\r\n    DECLARE hire_year DOUBLE;   #\u8bb0\u5f55\u5458\u5de5\u5165\u804c\u516c\u53f8\u7684\u5e74\u5934\r\n\r\n    #\u8d4b\u503c\r\n    SELECT salary INTO emp_sal FROM employees WHERE employee_id = emp_id;\r\n\r\n    SELECT DATEDIFF(CURDATE(),hire_date) \/ 365 INTO hire_year FROM employees WHERE employee_id = emp_id;\r\n\r\n    #\u5224\u65ad\r\n    IF emp_sal &lt; 9000 AND hire_year >= 5\r\n        THEN UPDATE employees SET salary = salary + 500 WHERE employee_id = emp_id;\r\n        ELSE UPDATE employees SET salary = salary + 100 WHERE employee_id = emp_id;\r\n        END IF;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL update_salary_by_eid2(103);\r\nCALL update_salary_by_eid2(104);\r\n\r\nSELECT * FROM employees\r\nWHERE employee_id IN (103,104);\r\n\r\n# \u4e3e\u4f8b4\uff1a\u58f0\u660e\u5b58\u50a8\u8fc7\u7a0b\u201cupdate_salary_by_eid3\u201d\uff0c\u5b9a\u4e49IN\u53c2\u6570emp_id\uff0c\u8f93\u5165\u5458\u5de5\u7f16\u53f7\u3002\r\n# \u5224\u65ad\u8be5\u5458\u5de5\u85aa\u8d44\u5982\u679c\u4f4e\u4e8e9000\u5143\uff0c\u5c31\u66f4\u65b0\u85aa\u8d44\u4e3a9000\u5143\uff1b\u85aa\u8d44\u5982\u679c\u5927\u4e8e\u7b49\u4e8e9000\u5143\u4e14\r\n# \u4f4e\u4e8e10000\u7684\uff0c\u4f46\u662f\u5956\u91d1\u6bd4\u4f8b\u4e3aNULL\u7684\uff0c\u5c31\u66f4\u65b0\u5956\u91d1\u6bd4\u4f8b\u4e3a0.01\uff1b\u5176\u4ed6\u7684\u6da8\u85aa100\u5143\u3002\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE update_salary_by_eid3(IN emp_id INT)\r\nBEGIN\r\n    #\u58f0\u660e\u53d8\u91cf\r\n    DECLARE emp_sal DOUBLE; #\u8bb0\u5f55\u5458\u5de5\u5de5\u8d44\r\n    DECLARE bonus DOUBLE;   #\u8bb0\u5f55\u5458\u5de5\u7684\u5956\u91d1\u7387\r\n\r\n    SELECT salary INTO emp_sal FROM employees WHERE employee_id = emp_id;\r\n    SELECT commission_pct INTO bonus FROM employees WHERE employee_id = emp_id;\r\n\r\n    #\u5224\u65ad\r\n    IF emp_sal &lt; 9000\r\n        THEN UPDATE employees SET salary = 9000 WHERE employee_id = emp_id;\r\n    ELSEIF emp_sal &lt; 10000 AND bonus IS NULL\r\n        THEN UPDATE employees SET commission_pct = 0.01 WHERE employee_id = emp_id;\r\n    ELSE\r\n        UPDATE employees SET salary = salary + 100 WHERE employee_id = emp_id;\r\n        END IF;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL update_salary_by_eid3(102);\r\nCALL update_salary_by_eid3(103);\r\nCALL update_salary_by_eid3(104);\r\n\r\nSELECT *\r\nFROM employees\r\nWHERE employee_id IN (102,103,104);\r\n\r\n# 3.2 \u5206\u652f\u7ed3\u6784\u4e4bcase\r\n\r\n#\u4e3e\u4f8b\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE test_case()\r\nBEGIN\r\n    #\u6f14\u793a1\uff1acase...when...then...\r\n    \/*\r\n    DECLARE var INT DEFAULT 2;\r\n\r\n    CASE var\r\n        WHEN 1 THEN SELECT 'var = 1';\r\n        WHEN 2 THEN SELECT 'var = 2';\r\n        WHEN 3 THEN SELECT 'var = 3';\r\n        ELSE SELECT 'other value';\r\n        END CASE;\r\n     *\/\r\n    #\u6f14\u793a2\uff1acase when...then...\r\n    DECLARE var1 INT DEFAULT 10;\r\n    CASE\r\n        WHEN var1 >= 100 THEN SELECT '\u4e09\u4f4d\u6570';\r\n        WHEN var1 >= 10 THEN SELECT '\u4e24\u4f4d\u6570';\r\n        ELSE SELECT '\u4e2a\u4f4d\u6570';\r\n        END CASE;\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL test_case();\r\n\r\nDROP PROCEDURE test_case;\r\n\r\n# \u4e3e\u4f8b2\uff1a\u58f0\u660e\u5b58\u50a8\u8fc7\u7a0b\u201cupdate_salary_by_eid4\u201d\uff0c\u5b9a\u4e49IN\u53c2\u6570emp_id\uff0c\u8f93\u5165\u5458\u5de5\u7f16\u53f7\u3002\r\n# \u5224\u65ad\u8be5\u5458\u5de5\u85aa\u8d44\u5982\u679c\u4f4e\u4e8e9000\u5143\uff0c\u5c31\u66f4\u65b0\u85aa\u8d44\u4e3a9000\u5143\uff1b\u85aa\u8d44\u5927\u4e8e\u7b49\u4e8e9000\u5143\u4e14\u4f4e\u4e8e10000\u7684\uff0c\r\n# \u4f46\u662f\u5956\u91d1\u6bd4\u4f8b\u4e3aNULL\u7684\uff0c\u5c31\u66f4\u65b0\u5956\u91d1\u6bd4\u4f8b\u4e3a0.01\uff1b\u5176\u4ed6\u7684\u6da8\u85aa100\u5143\u3002\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE update_salary_by_eid4(IN emp_id INT)\r\nBEGIN\r\n   #\u5c40\u90e8\u53d8\u91cf\u7684\u58f0\u660e\r\n    DECLARE emp_sal DOUBLE; #\u8bb0\u5f55\u5458\u5de5\u7684\u5de5\u8d44\r\n   DECLARE bonus DOUBLE;    #\u8bb0\u5f55\u5458\u5de5\u7684\u5956\u91d1\u7387\r\n\r\n    #\u5c40\u90e8\u53d8\u91cf\u7684\u8d4b\u503c\r\n    SELECT salary INTO emp_sal FROM employees WHERE employee_id = emp_id;\r\n   SELECT commission_pct INTO bonus FROM employees WHERE employee_id = emp_id;\r\n   CASE\r\n       WHEN emp_sal &lt; 9000 THEN UPDATE employees SET salary = 9000 WHERE employee_id = emp_id;\r\n       WHEN emp_sal &lt; 10000 AND bonus IS NULL THEN UPDATE employees SET commission_pct = 0.01\r\n                                                        WHERE employee_id = emp_id;\r\n       ELSE UPDATE employees SET salary = salary + 100 WHERE employee_id = emp_id;\r\n       END CASE;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL update_salary_by_eid4(103);\r\nCALL update_salary_by_eid4(104);\r\nCALL update_salary_by_eid4(105);\r\n\r\nSELECT *\r\nFROM employees\r\nWHERE employee_id IN (103,104,105);\r\n\r\n# \u4e3e\u4f8b3\uff1a\u58f0\u660e\u5b58\u50a8\u8fc7\u7a0bupdate_salary_by_eid5\uff0c\u5b9a\u4e49IN\u53c2\u6570emp_id\uff0c\u8f93\u5165\u5458\u5de5\u7f16\u53f7\u3002\r\n# \u5224\u65ad\u8be5\u5458\u5de5\u7684\u5165\u804c\u5e74\u9650\uff0c\u5982\u679c\u662f0\u5e74\uff0c\u85aa\u8d44\u6da850\uff1b\u5982\u679c\u662f1\u5e74\uff0c\u85aa\u8d44\u6da8100\uff1b\r\n# \u5982\u679c\u662f2\u5e74\uff0c\u85aa\u8d44\u6da8200\uff1b\u5982\u679c\u662f3\u5e74\uff0c\u85aa\u8d44\u6da8300\uff1b\u5982\u679c\u662f4\u5e74\uff0c\u85aa\u8d44\u6da8400\uff1b\u5176\u4ed6\u7684\u6da8\u85aa500\u3002\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE update_salary_by_eid5(IN emp_id INT)\r\nBEGIN\r\n   #\u58f0\u660e\u5c40\u90e8\u53d8\u91cf\r\n    DECLARE hire_year INT;    #\u8bb0\u5f55\u5458\u5de5\u5165\u804c\u516c\u53f8\u7684\u603b\u65f6\u95f4\uff08\u5355\u4f4d\uff1a\u5e74\uff09\r\n\r\n    #\u8d4b\u503c\r\n    SELECT ROUND(DATEDIFF(CURDATE(),hire_date) \/ 365) INTO hire_year\r\n    FROM employees WHERE employee_id = emp_id;\r\n\r\n   #\u5224\u65ad\r\n    CASE hire_year\r\n        WHEN 0 THEN UPDATE employees SET salary = salary + 50 WHERE employee_id = emp_id;\r\n        WHEN 1 THEN UPDATE employees SET salary = salary + 100 WHERE employee_id = emp_id;\r\n        WHEN 2 THEN UPDATE employees SET salary = salary + 200 WHERE employee_id = emp_id;\r\n        WHEN 3 THEN UPDATE employees SET salary = salary + 300 WHERE employee_id = emp_id;\r\n        WHEN 4 THEN UPDATE employees SET salary = salary + 400 WHERE employee_id = emp_id;\r\n        ELSE UPDATE employees SET salary = salary + 500 WHERE employee_id = emp_id;\r\n        END CASE;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL update_salary_by_eid5(101);\r\n\r\nSELECT *\r\nFROM employees;\r\n\r\nDROP PROCEDURE update_salary_by_eid5;\r\n\r\n# 4.1 \u5faa\u73af\u7ed3\u6784\u4e4bLOOP\r\n\/*\r\n &#91;loop_label:] LOOP\r\n        \u5faa\u73af\u6267\u884c\u7684\u8bed\u53e5\r\n END LOOP &#91;loop_label]\r\n\r\n *\/\r\n#\u4e3e\u4f8b1\uff1a\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE test_loop()\r\nBEGIN\r\n   #\u58f0\u660e\u5c40\u90e8\u53d8\u91cf\r\n    DECLARE num INT DEFAULT 1;\r\n\r\n   loop_label:LOOP\r\n       #\u91cd\u65b0\u8d4b\u503c\r\n       SET num = num + 1;\r\n\r\n       #\u53ef\u4ee5\u8003\u8651\u67d0\u4e2a\u4ee3\u7801\u7a0b\u5e8f\u53cd\u590d\u6267\u884c\u3002\uff08\u7565\uff09\r\n\r\n       IF num >= 10 THEN LEAVE loop_label;\r\n       END IF;\r\n   END LOOP loop_label;\r\n\r\n   #\u67e5\u770bnum\r\n    SELECT num;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL test_loop();\r\n\r\n#\u4e3e\u4f8b2\uff1a\r\n# \u5f53\u5e02\u573a\u73af\u5883\u53d8\u597d\u65f6\uff0c\u516c\u53f8\u4e3a\u4e86\u5956\u52b1\u5927\u5bb6\uff0c\u51b3\u5b9a\u7ed9\u5927\u5bb6\u6da8\u5de5\u8d44\u3002\r\n# \u58f0\u660e\u5b58\u50a8\u8fc7\u7a0b\u201cupdate_salary_loop()\u201d\uff0c\u58f0\u660eOUT\u53c2\u6570num\uff0c\u8f93\u51fa\u5faa\u73af\u6b21\u6570\u3002\r\n# \u5b58\u50a8\u8fc7\u7a0b\u4e2d\u5b9e\u73b0\u5faa\u73af\u7ed9\u5927\u5bb6\u6da8\u85aa\uff0c\u85aa\u8d44\u6da8\u4e3a\u539f\u6765\u76841.1\u500d\u3002\u76f4\u5230\u5168\u516c\u53f8\u7684\u5e73\r\n# \u5747\u85aa\u8d44\u8fbe\u523012000\u7ed3\u675f\u3002\u5e76\u7edf\u8ba1\u5faa\u73af\u6b21\u6570\u3002\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE update_salary_loop(OUT num INT)\r\nBEGIN\r\n    #\u58f0\u660e\u53d8\u91cf\r\n    DECLARE avg_sal DOUBLE; #\u8bb0\u5f55\u5458\u5de5\u7684\u5e73\u5747\u5de5\u8d44\r\n\r\n    DECLARE loop_count INT DEFAULT 0; #\u8bb0\u5f55\u5faa\u73af\u7684\u6b21\u6570\r\n\r\n    # \u2460 \u521d\u59cb\u5316\u6761\u4ef6\r\n    #\u83b7\u53d6\u5458\u5de5\u7684\u5e73\u5747\u5de5\u8d44\r\n    SELECT AVG(salary) INTO avg_sal FROM employees;\r\n\r\n    loop_lab:LOOP\r\n        #\u2461 \u5faa\u73af\u6761\u4ef6\r\n        #\u7ed3\u675f\u5faa\u73af\u7684\u6761\u4ef6\r\n        IF avg_sal >= 12000\r\n            THEN LEAVE loop_lab;\r\n            END IF;\r\n\r\n        # \u5faa\u73af\u4f53\r\n        #\u5982\u679c\u4f4e\u4e8e12000\uff0c\u66f4\u65b0\u5458\u5de5\u7684\u5de5\u8d44\r\n        UPDATE employees SET salary = salary * 1.1;\r\n\r\n        #\u2463 \u8fed\u4ee3\u6761\u4ef6\r\n        #\u66f4\u65b0avg_sal\u53d8\u91cf\u7684\u503c\r\n        SELECT AVG(salary) INTO avg_sal FROM employees;\r\n\r\n        #\u8bb0\u5f55\u5faa\u73af\u6b21\u6570\r\n        SET loop_count = loop_count + 1;\r\n\r\n    END LOOP loop_lab;\r\n\r\n    #\u7ed9num\u8d4b\u503c\r\n    SET num = loop_count;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\nSELECT AVG(salary) FROM employees;\r\n\r\nCALL update_salary_loop(@num);\r\nSELECT @num;\r\n\r\n# 4.2 \u5faa\u73af\u7ed3\u6784\u4e4bWHILE\r\n\/*\r\n &#91;while_label:] WHILE \u5faa\u73af\u6761\u4ef6 DO\r\n        \u5faa\u73af\u4f53\r\n END WHILE &#91;while_label];\r\n\r\n *\/\r\n#\u4e3e\u4f8b1\uff1a\r\nDELIMITER \/\/\r\nCREATE PROCEDURE test_while()\r\n\r\nBEGIN\r\n    #\u521d\u59cb\u5316\u6761\u4ef6\r\n   DECLARE num INT DEFAULT 1;\r\n    #\u5faa\u73af\u6761\u4ef6\r\n   WHILE num &lt;= 10 DO\r\n       #\u5faa\u73af\u4f53\uff08\u7565\uff09\r\n\r\n       #\u8fed\u4ee3\u6761\u4ef6\r\n       SET num = num + 1;\r\n       END WHILE;\r\n\r\n    #\u67e5\u8be2\r\n    SELECT num;\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\nDROP PROCEDURE test_while;\r\n\r\nCALL test_while();\r\n\r\n# \u4e3e\u4f8b2\uff1a\u5e02\u573a\u73af\u5883\u4e0d\u597d\u65f6\uff0c\u516c\u53f8\u4e3a\u4e86\u6e21\u8fc7\u96be\u5173\uff0c\u51b3\u5b9a\u6682\u65f6\u964d\u4f4e\u5927\u5bb6\u7684\u85aa\u8d44\u3002\r\n# \u58f0\u660e\u5b58\u50a8\u8fc7\u7a0b\u201cupdate_salary_while()\u201d\uff0c\u58f0\u660eOUT\u53c2\u6570num\uff0c\u8f93\u51fa\u5faa\u73af\u6b21\u6570\u3002\r\n# \u5b58\u50a8\u8fc7\u7a0b\u4e2d\u5b9e\u73b0\u5faa\u73af\u7ed9\u5927\u5bb6\u964d\u85aa\uff0c\u85aa\u8d44\u964d\u4e3a\u539f\u6765\u768490%\u3002\u76f4\u5230\u5168\u516c\u53f8\u7684\u5e73\u5747\u85aa\u8d44\r\n# \u8fbe\u52305000\u7ed3\u675f\u3002\u5e76\u7edf\u8ba1\u5faa\u73af\u6b21\u6570\u3002\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE update_salary_while(OUT num INT)\r\nBEGIN\r\n    #\u58f0\u660e\u53d8\u91cf\r\n    DECLARE avg_sal DOUBLE; #\u8bb0\u5f55\u5e73\u5747\u5de5\u8d44\r\n    DECLARE while_count INT DEFAULT 0;  #\u8bb0\u5f55\u5faa\u73af\u6b21\u6570\r\n\r\n    #\u8d4b\u503c\r\n    SELECT AVG(salary) INTO avg_sal FROM employees;\r\n\r\n    WHILE avg_sal > 5000 DO\r\n        UPDATE employees SET salary = salary * 0.9;\r\n\r\n        SET while_count = while_count + 1;\r\n\r\n        SELECT AVG(salary) INTO avg_sal FROM employees;\r\n\r\n        END WHILE;\r\n\r\n    #\u7ed9num\u8d4b\u503c\r\n    SET num = while_count;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL update_salary_while(@num);\r\nSELECT @num;\r\n\r\nSELECT AVG(salary) FROM employees;\r\n\r\n# 4.3 \u5faa\u73af\u7ed3\u6784\u4e4bREPEAT\r\n\r\n\/*\r\n&#91;repeat_label:] REPEAT\r\n        \u5faa\u73af\u4f53\u7684\u8bed\u53e5\r\nUNTIL \u7ed3\u675f\u5faa\u73af\u7684\u6761\u4ef6\u8868\u8fbe\u5f0f\r\nEND REPEAT &#91;repeat_label]\r\n *\/\r\n\r\n #\u4e3e\u4f8b1\uff1a\r\n\r\n DELIMITER \/\/\r\n\r\n CREATE PROCEDURE test_repeat()\r\n BEGIN\r\n    #\u58f0\u660e\u53d8\u91cf\r\n    DECLARE num INT DEFAULT 1;\r\n\r\n    REPEAT\r\n        SET num = num + 1;\r\n        UNTIL num >= 10\r\n    END REPEAT;\r\n\r\n    #\u67e5\u770b\r\n    SELECT num;\r\n\r\n END \/\/\r\n\r\n DELIMITER ;\r\n\r\n #\u8c03\u7528\r\n CALL test_repeat();\r\n\r\n# \u4e3e\u4f8b2\uff1a\u5f53\u5e02\u573a\u73af\u5883\u53d8\u597d\u65f6\uff0c\u516c\u53f8\u4e3a\u4e86\u5956\u52b1\u5927\u5bb6\uff0c\u51b3\u5b9a\u7ed9\u5927\u5bb6\u6da8\u5de5\u8d44\u3002\r\n# \u58f0\u660e\u5b58\u50a8\u8fc7\u7a0b\u201cupdate_salary_repeat()\u201d\uff0c\u58f0\u660eOUT\u53c2\u6570num\uff0c\u8f93\u51fa\u5faa\u73af\u6b21\u6570\u3002\r\n# \u5b58\u50a8\u8fc7\u7a0b\u4e2d\u5b9e\u73b0\u5faa\u73af\u7ed9\u5927\u5bb6\u6da8\u85aa\uff0c\u85aa\u8d44\u6da8\u4e3a\u539f\u6765\u76841.15\u500d\u3002\u76f4\u5230\u5168\u516c\u53f8\u7684\u5e73\u5747\r\n# \u85aa\u8d44\u8fbe\u523013000\u7ed3\u675f\u3002\u5e76\u7edf\u8ba1\u5faa\u73af\u6b21\u6570\u3002\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE update_salary_repeat(OUT num INT)\r\nBEGIN\r\n    #\u58f0\u660e\u53d8\u91cf\r\n    DECLARE avg_sal DOUBLE; #\u8bb0\u5f55\u5e73\u5747\u5de5\u8d44\r\n    DECLARE repeat_count INT DEFAULT 0; #\u8bb0\u5f55\u5faa\u73af\u6b21\u6570\r\n\r\n    #\u8d4b\u503c\r\n    SELECT AVG(salary) INTO avg_sal FROM employees;\r\n\r\n    REPEAT\r\n        UPDATE employees SET salary = salary * 1.15;\r\n        SET repeat_count = repeat_count + 1;\r\n\r\n        SELECT AVG(salary) INTO avg_sal FROM employees;\r\n\r\n        UNTIL avg_sal >= 13000\r\n\r\n    END REPEAT;\r\n\r\n    #\u7ed9num\u8d4b\u503c\r\n    SET num = repeat_count;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL update_salary_repeat(@num);\r\nSELECT @num;\r\n\r\nSELECT AVG(salary) FROM employees;\r\n\r\n\/*\r\n \u51e1\u662f\u5faa\u73af\u7ed3\u6784\uff0c\u4e00\u5b9a\u5177\u59074\u4e2a\u8981\u7d20\uff1a\r\n 1. \u521d\u59cb\u5316\u6761\u4ef6\r\n 2. \u5faa\u73af\u6761\u4ef6\r\n 3. \u5faa\u73af\u4f53\r\n 4. \u8fed\u4ee3\u6761\u4ef6\r\n\r\n *\/\r\n\r\n # 5.1 LEAVE\u7684\u4f7f\u7528\r\n\/*\r\n\u4e3e\u4f8b1\uff1a\u521b\u5efa\u5b58\u50a8\u8fc7\u7a0b \u201cleave_begin()\u201d\uff0c\u58f0\u660eINT\u7c7b\u578b\u7684IN\u53c2\u6570num\u3002\u7ed9BEGIN...END\u52a0\u6807\u8bb0\u540d\uff0c\u5e76\u5728BEGIN...END\u4e2d\u4f7f\u7528IF\u8bed\u53e5\u5224\u65adnum\u53c2\u6570\u7684\u503c\u3002\r\n\r\n    \u5982\u679cnum&lt;=0\uff0c\u5219\u4f7f\u7528LEAVE\u8bed\u53e5\u9000\u51faBEGIN...END\uff1b\r\n    \u5982\u679cnum=1\uff0c\u5219\u67e5\u8be2\u201cemployees\u201d\u8868\u7684\u5e73\u5747\u85aa\u8d44\uff1b\r\n    \u5982\u679cnum=2\uff0c\u5219\u67e5\u8be2\u201cemployees\u201d\u8868\u7684\u6700\u4f4e\u85aa\u8d44\uff1b\r\n    \u5982\u679cnum>2\uff0c\u5219\u67e5\u8be2\u201cemployees\u201d\u8868\u7684\u6700\u9ad8\u85aa\u8d44\u3002\r\n\r\nIF\u8bed\u53e5\u7ed3\u675f\u540e\u67e5\u8be2\u201cemployees\u201d\u8868\u7684\u603b\u4eba\u6570\u3002\r\n\r\n *\/\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE leave_begin(IN num INT)\r\n\r\nbegin_label:BEGIN\r\n    IF num &lt;= 0\r\n        THEN LEAVE begin_label;\r\n    ELSEIF num = 1\r\n        THEN SELECT AVG(salary) FROM employees;\r\n    ELSEIF num = 2\r\n        THEN SELECT MIN(salary) FROM employees;\r\n    ELSE\r\n        SELECT MAX(salary) FROM employees;\r\n        END IF;\r\n\r\n    #\u67e5\u8be2\u603b\u4eba\u6570\r\n    SELECT COUNT(*) FROM employees;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL leave_begin(1);\r\n\r\n# \u4e3e\u4f8b2\uff1a\u5f53\u5e02\u573a\u73af\u5883\u4e0d\u597d\u65f6\uff0c\u516c\u53f8\u4e3a\u4e86\u6e21\u8fc7\u96be\u5173\uff0c\u51b3\u5b9a\u6682\u65f6\u964d\u4f4e\u5927\u5bb6\u7684\u85aa\u8d44\u3002\r\n# \u58f0\u660e\u5b58\u50a8\u8fc7\u7a0b\u201cleave_while()\u201d\uff0c\u58f0\u660eOUT\u53c2\u6570num\uff0c\u8f93\u51fa\u5faa\u73af\u6b21\u6570\uff0c\u5b58\u50a8\u8fc7\u7a0b\u4e2d\u4f7f\u7528WHILE\r\n# \u5faa\u73af\u7ed9\u5927\u5bb6\u964d\u4f4e\u85aa\u8d44\u4e3a\u539f\u6765\u85aa\u8d44\u768490%\uff0c\u76f4\u5230\u5168\u516c\u53f8\u7684\u5e73\u5747\u85aa\u8d44\u5c0f\u4e8e\u7b49\u4e8e10000\uff0c\u5e76\u7edf\u8ba1\u5faa\u73af\u6b21\u6570\u3002\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE leave_while(OUT num INT)\r\nBEGIN\r\n   #\r\n    DECLARE avg_sal DOUBLE; #\u8bb0\u5f55\u5e73\u5747\u5de5\u8d44\r\n    DECLARE while_count INT DEFAULT 0;  #\u8bb0\u5f55\u5faa\u73af\u6b21\u6570\r\n\r\n    SELECT AVG(salary) INTO avg_sal FROM employees; #\u2460 \u521d\u59cb\u5316\u6761\u4ef6\r\n\r\n   while_label:WHILE TRUE DO    #\u2461 \u5faa\u73af\u6761\u4ef6\r\n\r\n       #\u2462 \u5faa\u73af\u4f53\r\n       IF avg_sal &lt;= 10000 THEN\r\n           LEAVE while_label;\r\n           END IF;\r\n\r\n       UPDATE employees SET salary = salary * 0.9;\r\n       SET while_count = while_count + 1;\r\n\r\n       #\u2463 \u8fed\u4ee3\u6761\u4ef6\r\n       SELECT AVG(salary) INTO avg_sal FROM employees;\r\n\r\n       END WHILE;\r\n\r\n   #\u8d4b\u503c\r\n    SET num = while_count;\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\nCALL leave_while(@num);\r\nSELECT @num;\r\n\r\nSELECT AVG(salary) FROM employees;\r\n\r\n# 5.2 ITERATE\u7684\u4f7f\u7528\r\n\/*\r\n \u4e3e\u4f8b\uff1a \u5b9a\u4e49\u5c40\u90e8\u53d8\u91cfnum\uff0c\u521d\u59cb\u503c\u4e3a0\u3002\u5faa\u73af\u7ed3\u6784\u4e2d\u6267\u884cnum + 1\u64cd\u4f5c\u3002\r\n    \u5982\u679cnum &lt; 10\uff0c\u5219\u7ee7\u7eed\u6267\u884c\u5faa\u73af\uff1b\r\n    \u5982\u679cnum > 15\uff0c\u5219\u9000\u51fa\u5faa\u73af\u7ed3\u6784\uff1b\r\n\r\n *\/\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE test_iterate()\r\n\r\nBEGIN\r\n   DECLARE num INT DEFAULT 0;\r\n\r\n   loop_label:LOOP\r\n       #\u8d4b\u503c\r\n       SET num = num + 1;\r\n\r\n       IF num &lt; 10\r\n           THEN ITERATE loop_label;\r\n        ELSEIF num > 15\r\n           THEN LEAVE loop_label;\r\n           END IF;\r\n\r\n       SELECT 'RichieZhang\uff1a\u4eca\u5929\u5929\u6c14\u771f\u597d\u554a\uff01';\r\n\r\n   END LOOP;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\nCALL test_iterate();\r\n\r\nSELECT * FROM employees;\r\n\r\n# 6. \u6e38\u6807\u7684\u4f7f\u7528\r\n\/*\r\n \u6e38\u6807\u4f7f\u7528\u7684\u6b65\u9aa4\uff1a\r\n \u2460 \u58f0\u660e\u6e38\u6807\r\n \u2461 \u6253\u5f00\u6e38\u6807\r\n \u2462 \u4f7f\u7528\u6e38\u6807\uff08\u4ece\u6e38\u6807\u4e2d\u83b7\u53d6\u6570\u636e\uff09\r\n \u2463 \u5173\u95ed\u6e38\u6807\r\n\r\n *\/\r\n\r\n#\u4e3e\u4f8b\uff1a\u521b\u5efa\u5b58\u50a8\u8fc7\u7a0b\u201cget_count_by_limit_total_salary()\u201d\uff0c\u58f0\u660eIN\u53c2\u6570 limit_total_salary\uff0c\r\n#DOUBLE\u7c7b\u578b\uff1b\u58f0\u660eOUT\u53c2\u6570total_count\uff0cINT\u7c7b\u578b\u3002\u51fd\u6570\u7684\u529f\u80fd\u53ef\u4ee5\u5b9e\u73b0\u7d2f\u52a0\u85aa\u8d44\u6700\u9ad8\u7684\u51e0\u4e2a\u5458\u5de5\u7684\u85aa\u8d44\u503c\uff0c\r\n#\u76f4\u5230\u85aa\u8d44\u603b\u548c\u8fbe\u5230limit_total_salary\u53c2\u6570\u7684\u503c\uff0c\u8fd4\u56de\u7d2f\u52a0\u7684\u4eba\u6570\u7ed9total_count\u3002\r\n\r\nDELIMITER \/\/\r\n\r\nCREATE PROCEDURE get_count_by_limit_total_salary(IN limit_total_salary DOUBLE,OUT total_count INT)\r\nBEGIN\r\n   #\u58f0\u660e\u5c40\u90e8\u53d8\u91cf\r\n    DECLARE sum_sal DOUBLE DEFAULT 0.0; #\u8bb0\u5f55\u7d2f\u52a0\u7684\u5de5\u8d44\u603b\u989d\r\n    DECLARE emp_sal DOUBLE; #\u8bb0\u5f55\u6bcf\u4e00\u4e2a\u5458\u5de5\u7684\u5de5\u8d44\r\n    DECLARE emp_count INT DEFAULT 0; #\u8bb0\u5f55\u7d2f\u52a0\u7684\u4eba\u6570\r\n\r\n    # 1. \u58f0\u660e\u6e38\u6807\r\n    DECLARE emp_cursor CURSOR FOR SELECT salary FROM employees ORDER BY salary DESC;\r\n\r\n    # 2. \u6253\u5f00\u6e38\u6807\r\n    OPEN emp_cursor;\r\n\r\n   REPEAT\r\n\r\n    # 3. \u4f7f\u7528\u6e38\u6807\r\n    FETCH emp_cursor INTO emp_sal;\r\n\r\n    SET sum_sal = sum_sal + emp_sal;\r\n    SET emp_count = emp_count + 1;\r\n    UNTIL sum_sal >= limit_total_salary\r\n        END REPEAT;\r\n\r\n   SET total_count = emp_count;\r\n\r\n   # 4. \u5173\u95ed\u6e38\u6807\r\n    CLOSE emp_cursor;\r\n\r\nEND \/\/\r\n\r\nDELIMITER ;\r\n\r\n#\u8c03\u7528\r\n\r\nCALL get_count_by_limit_total_salary(200000,@total_count);\r\nSELECT @total_count;<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[47],"class_list":["post-1570","post","type-post","status-publish","format-standard","hentry","category-mysql-code","tag-mysql"],"_links":{"self":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1570"}],"collection":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1570"}],"version-history":[{"count":1,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1570\/revisions"}],"predecessor-version":[{"id":1571,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1570\/revisions\/1571"}],"wp:attachment":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1570"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1570"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1570"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}